chasher.h

//==========================================================================
//   CHASHER.H  - part of
//                     OMNeT++/OMNEST
//            Discrete System Simulation in C++
//
//==========================================================================

/*--------------------------------------------------------------*
  Copyright (C) 1992-2017 Andras Varga
  Copyright (C) 2006-2017 OpenSim Ltd.

  This file is distributed WITHOUT ANY WARRANTY. See the file
  `license' for details on this and other legal matters.
*--------------------------------------------------------------*/

#ifndef __OMNETPP_CHASHER_H
#define __OMNETPP_CHASHER_H

#include <cstdint>
#include <cstring>
#include <cstdlib>
#include "simkerneldefs.h"
#include "cobject.h"
#include "cexception.h"

namespace omnetpp {


class SIM_API cHasher : noncopyable
{
  private:
    uint32_t value;

    void merge(uint32_t x) {
        // rotate value left by one bit, and xor with new data
        uint32_t carry = (value & 0x80000000U) >> 31;
        value = ((value<<1)|carry) ^ x;
    }

    void merge2(uint64_t x) {
        merge((uint32_t)x);
        merge((uint32_t)(x>>32));
    }

  public:
    cHasher() {ASSERT(sizeof(uint32_t)==4); ASSERT(sizeof(double)==8); value = 0;}

    void reset() {value = 0;}
    void add(const char *p, size_t length);
    void add(char d)           {merge((uint32_t)d);}
    void add(short d)          {merge((uint32_t)d);}
    void add(int d)            {merge((uint32_t)d);}
    void add(long d)           {int64_t tmp=d; merge2((uint64_t)tmp);}
    void add(long long d)      {merge2((uint64_t)d);}
    void add(unsigned char d)  {merge((uint32_t)d);}
    void add(unsigned short d) {merge((uint32_t)d);}
    void add(unsigned int d)   {merge((uint32_t)d);}
    void add(unsigned long d)  {uint64_t tmp=d; merge2(tmp);}
    void add(unsigned long long d)  {merge2(d);}
    // note: safe(r) type punning, see http://cocoawithlove.decenturl.com/type-punning
    void add(double d)         {union _ {double d; uint64_t i;}; merge2(((union _ *)&d)->i);}
    void add(const char *s)    {if (s) add(s, strlen(s)+1); else add(0);}

    uint32_t getHash() const {return value;}

    uint32_t parse(const char *hash) const;

    bool equals(const char *hash) const;

    std::string str() const;
};

}  // namespace omnetpp

#endif